scholarly journals Temporal patterns in the acoustic signals of beaked whales at Cross Seamount

2008 ◽  
Vol 4 (2) ◽  
pp. 208-211 ◽  
Author(s):  
D.W Johnston ◽  
M McDonald ◽  
J Polovina ◽  
R Domokos ◽  
S Wiggins ◽  
...  

Seamounts may influence the distribution of marine mammals through a combination of increased ocean mixing, enhanced local productivity and greater prey availability. To study the effects of seamounts on the presence and acoustic behaviour of cetaceans, we deployed a high-frequency acoustic recording package on the summit of Cross Seamount during April through October 2005. The most frequently detected cetacean vocalizations were echolocation sounds similar to those produced by ziphiid and mesoplodont beaked whales together with buzz-type signals consistent with prey-capture attempts. Beaked whale signals occurred almost entirely at night throughout the six-month deployment. Measurements of prey presence with a Simrad EK-60 fisheries acoustics echo sounder indicate that Cross Seamount may enhance local productivity in near-surface waters. Concentrations of micronekton were aggregated over the seamount in near-surface waters at night, and dense concentrations of nekton were detected across the surface of the summit. Our results suggest that seamounts may provide enhanced foraging opportunities for beaked whales during the night through a combination of increased productivity, vertical migrations by micronekton and local retention of prey. Furthermore, the summit of the seamount may act as a barrier against which whales concentrate prey.

2008 ◽  
Vol 25 (9) ◽  
pp. 1710-1716 ◽  
Author(s):  
Jiayi Pan ◽  
David A. Jay

Abstract The utility of the acoustic Doppler current profiler (ADCP) for sampling small time and space scales of coastal environments can be enhanced by mounting a high-frequency (1200 kHz) ADCP on an oscillating towed body. This approach requires both an external reference to convert the measured shears to velocities in the earth coordinates and a method to determine the towed body velocities. During the River Influence on the Shelf Ecosystems (RISE) project cruise, a high-frequency (1200 kHz) and narrowbeam ADCP with mode 12 sampling was mounted on a TRIAXUS oscillating towfish, which steers a 3D path behind the ship. This deployment approach extended the vertical range of the ADCP and allowed it to sample near-surface waters outside the ship’s wake. The measurements from a ship-mounted 1200-kHz narrowbeam ADCP are used as references for TRIAXUS ADCP data, and a method of overlapping bins is employed to recover the entire vertical range of the TRIAXUS ADCP. The TRIAXUS vehicle horizontal velocities are obtained by removing the derived ocean current velocity from the TRIAXUS ADCP measurements. The results show that the method is practical.


2006 ◽  
Vol 120 (5) ◽  
pp. 3015-3015
Author(s):  
Sean M. Wiggins ◽  
Chris Garsha ◽  
Greg Campbell ◽  
John A. Hildebrand

2020 ◽  
Vol 644 ◽  
pp. 199-214 ◽  
Author(s):  
J Barlow ◽  
GS Schorr ◽  
EA Falcone ◽  
D Moretti

Depth distributions were analyzed from a study of 19 Cuvier’s beaked whales Ziphius cavirostris that were tagged with satellite transmitting instruments off southern California, USA. Over 113000 depth measurements were made over the equivalent of ~200 sampling days. The mean foraging depth was 1182 m (SD = 305 m), and the mean of the maximum depth of all foraging dives was 1427 m (SD = 298 m). Mean foraging depths increased with seafloor depths up to a maximum of ~1300 m at a seafloor depth of 1900 m, but decreased slightly to a mean of ~1200 m at seafloor depths of 2000-4000 m. Near-bottom habitat appears to be important for foraging; whales spent ~30% of their foraging time within 200 m of the bottom at seafloor depths of 1000-2000 m. However, little foraging time was spent near the bottom at seafloor depths greater than 2000 m. The percentage of time spent at near-surface depths (<50 m) was more than twice as high at night (25%) than during the day (12%). Lunar light also appears to affect diving, with 28% of dark nights and only 17% of brightly moonlit nights spent at these near-surface depths. The apparent avoidance of surface waters during daytime and on brightly moonlit nights is consistent with avoidance of visual predators. A considerably greater fraction of time was spent foraging at night (24.8%) than during the day (15.7%), possibly due to energetic constraints imposed by predator avoidance during the day.


2005 ◽  
Vol 11 (4) ◽  
pp. 302 ◽  
Author(s):  
Matthew S. Leslie ◽  
Aisake Batibasaga ◽  
Diana S. Weber ◽  
David Olson ◽  
Howard C. Rosenbaum

LIttle Is known about the conservation status and geographic range of beaked whales. This note provides the first record of a Blainville's Beaked Whale Mesoplodon densirostris in Fijian waters, and contributes to the available knowledge of a species poorly known in the South Pacific region. On 11 November 2003, a female beaked whale stranded near Viti Levu, Fiji. A lack of suitable references and unfamiliarity with diagnostic morphological characters inhibited species identification at the time of stranding. However, we were able to identify this specimen by using molecular genetic information and applying a diagnostic character approach. DNA sequences from the unknown specimen exhibited nucleotide character states that unambiguously identified it as a Blainville's Beaked Whale. Unfortunately, a lack of associated data collected in this particular event emphasizes a common situation around the world: untrained or poorly equipped personnel (municipalities, governmental agencies or local residents) must manage stranded marine mammals out of necessity. However, information from these events or opportunistic beach surveys assists In furthering research of conservation status and management needs.


2011 ◽  
Vol 92 (8) ◽  
pp. 1851-1864 ◽  
Author(s):  
Helen Otley ◽  
John Smith ◽  
Merel L. Dalebout

Records of beaked whales stranded in the Falkland Islands and at South Georgia were collated for the period 1866 to 2008. Thirty-eight records, involving at least seven species in four genera, were documented. Strap-toothed whales (Mesoplodon layardii Gray, 1865) were the most common species with 11 records, including two neonates. Andrews' beaked whales (M. bowdoini Andrews, 1908), Arnoux's beaked whales (Berardius arnuxii Duvernoy, 1851), Cuvier's beaked whales (Ziphius cavirostris Gray, 1823), Gray's beaked whale (M. grayi van Haast, 1876), Hector's beaked whales (M. hectori Gray, 1871) and southern bottlenose whales (Hyperoodon planifrons Flower, 1882) were recorded on three to five occasions. In several cases, records suggested potential temporal changes in range. For example, Arnoux's beaked whale has not been recorded in the Falkland Islands since 1965, whilst Gray's beaked whale was not recorded prior to 1981, and Andrews' beaked whale was not recorded before 1987. Although the number of records for each species is low, this could reflect changes in water temperatures and/or prey availability. Overall, this study confirms that the Falkland Islands–Tierra del Fuego region is one of the world's key areas for beaked whales.


2005 ◽  
Vol 117 (4) ◽  
pp. 2525-2525 ◽  
Author(s):  
Sean Wiggins ◽  
Chris Garsha ◽  
Kevin Hardy ◽  
John Hildebrand

Author(s):  
V.A. Bulanov ◽  
I.V. Korskov ◽  
A.V. Storozhenko ◽  
S.N. Sosedko

Описано применение акустического зондирования для исследования акустических характеристик верхнего слоя моря с использованием широкополосных остронаправленных инвертированных излучателей,устанавливаемых на дно. В основу метода положен принцип регистрации обратного рассеяния и отраженияот поверхности моря акустических импульсов с различной частотой, позволяющий одновременно измерятьрассеяние и поглощение звука и нелинейный акустический параметр морской воды. Многочастотное зондирование позволяет реализовать акустическую спектроскопию пузырьков в приповерхностных слоях моря,проводить оценку газосодержания и получать данные о спектре поверхностного волнения при различных состояниях моря вплоть до штормовых. Применение остронаправленных высокочастотных пучков ультразвукапозволяет разделить информацию о планктоне и пузырьках и определить с высоким пространственным разрешением структуру пузырьковых облаков, образующихся при обрушении ветровых волн, и структуру планктонных сообществ. Участие планктона в волновом движении в толще морской воды позволяет определитьпараметры внутренних волн спектр и распределение по амплитудам в различное время.This paper represents the application of acoustic probingfor the investigation of acoustical properties of the upperlayer of the sea using broadband narrow-beam invertedtransducers that are mounted on the sea bottom. Thismethod is based on the principle of the recording of thebackscattering and reflections of acoustic pulses of differentfrequencies from the sea surface. That simultaneouslyallows measuring scattering and absorption of the soundand non-linear acoustic parameter of seawater. Multifrequencyprobing allows performing acoustic spectroscopy ofbubbles in the near-surface layer of the sea, estimating gascontent, and obtaining data on the spectrum of the surfacewaves in various states of the sea up to a storm. Utilizationof the high-frequency narrow ultrasound beams allows us toseparate the information about plankton and bubbles and todetermine the structure of bubble clouds, created during thebreaking of wind waves, along with the structure of planktoncommunities with high spatial resolution. The participationof plankton in the wave motion in the seawater columnallows determining parameters of internal waves, such asspectrum and distribution of amplitudes at different times.


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Joëlle De Weerdt ◽  
Eric Angel Ramos ◽  
Etienne Pouplard ◽  
Marc Kochzius ◽  
Phillip Clapham

AbstractDocumenting marine mammal strandings provides important information needed to understand the occurrence and distribution patterns of species. Here, we report on strandings of cetaceans on the Pacific (n = 11) and Caribbean (n = 2) coasts of Nicaragua, documented opportunistically from 2014 to 2021. Strandings included three species of baleen whale (blue whale Balaenoptera musculus, Bryde’s whale Balaenoptera edeni, humpback whale Megaptera novaeangliae) and five species of toothed whale (dwarf sperm whale Kogia sima, Guiana dolphin Sotalia guianensis, pantropical spotted dolphin Stenella attenuata, spinner dolphin Stenella longirostris, Cuvier’s beaked whale Ziphius cavirostris). These are the first published accounts of blue whales, Bryde’s whales, dwarf sperm whales, and Cuvier’s beaked whales in Nicaraguan waters. Limited resources and the advanced decomposition of animals prevented necropsies in most cases, the identification of the causes of mortality in all cases, and the species identification of two dolphins. Information derived from these stranding events offers new insights into the occurrence of marine mammals on the Pacific and Caribbean coasts of Nicaragua and Central America.


2017 ◽  
Vol 74 (5) ◽  
pp. 716-726 ◽  
Author(s):  
Nicola Quick ◽  
Lindesay Scott-Hayward ◽  
Dina Sadykova ◽  
Doug Nowacek ◽  
Andrew Read

Active echo sounding devices are often employed for commercial or scientific purposes in the foraging habitats of marine mammals. We conducted an experiment off Cape Hatteras, North Carolina, USA, to assess whether the behavior of short-finned pilot whales (Globicephala macrorhynchus) changed when exposed to an EK60 scientific echo sounder. We attached digital acoustic recording tags (DTAGs) to nine individuals, five of which were exposed. A hidden Markov model to characterize diving states with and without exposure provided no evidence for a change in foraging behavior. However, generalized estimating equations to model changes in heading variance over the entire tag record under all experimental conditions showed a consistent increase in heading variance during exposure over all values of depth and pitch. This suggests that regardless of behavioral state, the whales changed their heading more frequently when the echo sounder was active. This response could represent increased vigilance in which whales maintained awareness of echo sounder location by increasing their heading variance and provides the first quantitative analysis on reactions of cetaceans to a scientific echo sounder.


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